You Think Infinite Mana Means You Can Do Whatever You Want?

"So you're saying the world you're from has a completely different history than ours—a world where mystery never faded and is fully ruled by fae?"

After listening to Artoria's explanation, Olga Marie summed it up:

"And in your world, the version of you who shares a name with our King Arthur didn't become king. Instead, someone named Guinevere—same name as your queen—became the King of Britain and wields the holy sword?"

"Yeah, more or less. That's the gist of it."

While sulkily jabbing at Guinevere's waist with her finger, Artoria muttered in response.

"Well, I mean... hmph. But what does any of this have to do with me?"

Guinevere's expression turned a little awkward.

"It's just a coincidence… I'm not that Guinevere. I've got nothing to do with Lancelot either, okay? Don't blame me for things I've never done…"

"But you totally stared at her for a while when we met her in Gloucester! You were clearly flustered—don't think I didn't notice!" Artoria suddenly twisted her fingers into Guinevere's side.

"Ugh—!"

Guinevere instantly began to stammer.

Seeing his reaction, Artoria twisted even harder.

He was numb.

What the hell, he really hadn't done anything! He just looked at her a bit longer, that's all! And come on, anyone would feel flustered if a beautiful girl helped adjust their collar, right?! You can't blame him for that!

—Wait, no. He couldn't think like that. Artoria had Fairy Eyes. She'd know.

But when he turned to look at her again, he realized she actually didn't seem to have picked up on that detail. That stunned him for a second.

"It really is strange, though," Roman mused. "Even though it's a completely different world, you have a Lancelot over there too? And she's a girl? Who also tried to go after your Guinevere? Sounds like some kind of fate, doesn't it?"

"Wait, no, stop right there! You can't just say stuff like that! She didn't try to romance me! I barely even interacted with her after my coronation!"

Guinevere emphasized:

"And besides, that whole Lancelot-Queen Guinevere affair—that's part of the Proper Human History, right? What does that have to do with Fairy Britain?"

"But your homeland is from Proper Human History, isn't it?"

Artoria said quietly.

"Wait a sec. Didn't you all say you were from another world? What's going on?" Olga Marie suddenly cut in.

She and the rest of Chaldea had just been quietly watching the drama unfold, but this tidbit contradicted their earlier story, so now she had to take it seriously.

And for the record, she was only watching because she didn't want to annoy their allies—not because she was actually into this kind of gossip!

"Er, technically yes. Just like how we stumbled into this world by chance, sometimes people from Proper Human History drift into Fairy Britain too. But the odds of that are like... meteor-strike-level rare."

Guinevere shook his head.

"And yeah, I'm not originally from Fairy Britain... But that's just a name coincidence! You can't just assume I'll cheat because I have the same name—that's not even scientific!"

"But we're in a world of magic," Cu Chulainn chimed in, grinning. "Servants aren't exactly scientific either."

"Oh, you wanna go?!" Guinevere flared up. "You've been egging this on the whole time!"

"Alright, alright, let's reel it back a bit," Roman jumped in, trying to calm things down. "Still, a world ruled by fae? Hard to imagine… What kind of history would lead to that?"

...But more importantly, why hasn't that world been pruned as a failed timeline?

And the fact that they keep referring to "Proper Human History" was definitely suspicious.

Still, now wasn't the time for questions like that, so Roman shelved the thought for later.

After that brief detour, everyone resumed their original mission. Now that Chaldea knew who Guinevere and Artoria really were, they felt much more reassured. Fighting that King Arthur guarding the Great Hollow didn't seem like such a suicide mission anymore.

That said, Mash was still having trouble with her Noble Phantasm, so on the way, Guinevere and Cu Chulainn made a point to let her take the lead in battles, hoping to help her get more comfortable with Servant combat.

But even by the time they reached the entrance of the Great Hollow, she still hadn't fully mastered it.

"Eh, it'll work out," Cu Chulainn said. "Guinevere, I'm leaving these girls in your hands!"

With that, he grabbed a certain Archer—an old flame of his—and disappeared to duel her.

"...Wait, why don't we all just gang up on that Archer and finish her off together before heading in?" Artoria asked, puzzled as she watched them vanish.

"You've got a point…" Guinevere sighed. "But hey, some rivalries run deep. Don't question it too hard. He's not gonna lose anyway."

"So… who is she exactly?" Olga Marie asked, curious. "Is this about more than just Cu Chulainn?"

"Well... the time to reveal that hasn't come yet, Director Marie. Please be patient—and hopeful," Guinevere said with a straight face.

"...I'm starting to understand why people hate riddlers so much."

Not long after, they reached the enormous underground cavern beneath Fuyuki.

Flames danced like a bridge between earth and sky, illuminating the chaotic, formless cavern. The air was thick with toxins, and the ceiling was so high it vanished into a purplish-red haze—like they'd stepped into a demon king's lair.

And at its heart, clad in pitch-black armor, Saber opened her eyes.

Her golden gaze locked immediately onto Artoria—and didn't move.

"So... that's me, the King Arthur of Proper Human History?"

Artoria gripped her staff, tense under that oppressive gaze.

"No, not exactly," Guinevere corrected. "That's the corrupted version of you—the reversed, blackened you."

"But there's no need to be afraid. I'm here."

He stepped forward, placing himself between Artoria and the black Saber.

"The one holding the holy sword is me. If anyone's going to fight her, it should be me."

"Oh?"

Black Saber glanced at his sword, then at Mash's shield, and raised an eyebrow.

"That sword… and that shield… Fascinating. Fate really is a strange thing."

"Then allow me to test you—alternate wielder of Excalibur!"

As her words fell, she vanished in an instant, launching herself forward. Guinevere didn't hesitate—he leapt to meet her.

The two clashed in the center of the field—holy light against cursed blackness. Their blades collided, unleashing torrents of magical energy that whipped the air into violent storms and shattered the ground.

But to the Chaldea girls watching, it was clear: Guinevere was losing the power struggle.

Of course, it was just brute force. Black Saber had the power of a dragon core and infinite mana from the Grail. Her sheer output had pushed her Strength stat to A—giving her the edge in raw power.

"It's fine! This is just the beginning!" Artoria called to the others, unfazed. "Guinevere was never the brawny type anyway!"

Exactly. He might not be as strong as a mana-spamming monster...

...But he was fast.

By the time Black Saber raised her second strike, Guinevere's second sword had already arrived.

"—!"

Black Saber quickly found herself overwhelmed by a flurry of lightning-fast strikes, retreating under the pressure.

Fast. Too fast.

Even Lancelot's sword never felt this relentless. One of her swings took twice as long as Guinevere's. But she was no rookie—within seconds, she changed tactics.

She dropped her guard and backed away, channeling all her energy into one mighty slash. She took a massive hit to the chest, blood spraying—but it gave her time.

And the next strike she launched was coated in enough mana to split mountains.

"?!"

Guinevere barely blocked it, but the impact sent him flying.

"Impressive swordplay," Black Saber said. "Now let's see if the rest of you is worthy of that blade."

She raised her sword.

"Dark Hammer of the False King, Reversed Light of the Dawn—devour all, Excalibur Morgan!"

When in doubt, nuke it.

Guinevere twitched at her recklessness, then raised his sword too.

"If that's what you want—then this is the battle to save the world! Excalibur!"

Fine. Ultimate moves it is.

His Excalibur wasn't shackled like hers. Pure, original, unbound. He wasn't afraid of a power duel.

The two beams clashed—light swallowed.

The entire Hollow shook. Cracks tore across the ground. The air screamed. The cavern ceiling collapsed, raining down debris—only to be vaporized mid-fall by the magical backlash.

And then, Guinevere's unbound Excalibur quickly overwhelmed the dark beam. The golden light surged forward...

But just then, in the corner of his eye, he caught sight of Artoria—her face pale, knees buckling.

Unlike Black Saber, fueled endlessly by the Grail, Guinevere's mana came from her.

—That original, unrestrained sword cost too much. She couldn't sustain it.

If he kept going, he would win.

But she might die.

Without a moment of hesitation, Guinevere cut off his beam, planting the sword upright and only using a trickle of mana to defend.

The black wave roared past, swallowing the golden glow.